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jrenaut
05-03-2012, 03:53 PM
So, I bought my bike the end of May 2011. I started off putting maybe 30 miles a week on it, and worked up to 50-75 miles a week. I do almost all of my riding in the city, and ride in all but the worst weather.

Today I brought my bike in to my LBS for warranty adjustments, and they said I need to replace the chain, cassette, crankset, and bottom bracket. I know I don't clean my chain and gears much, but does this seem excessive? Aside from cleaning, which I know I have to do better, are there other things to do to get a bit more life out of the drivetrain?

DismalScientist
05-03-2012, 04:45 PM
Are you sure they didn't suggest you overhaul the bottom bracket (i.e. open it up, clean it out, and regrease the thing, replacing any worn parts)? If the teeth aren't worn on the crank or the cassette (and the cassette spins fine), I wouldn't change it. Is the chain stretched? Are there any symptom of impending doom? If not, I would think about changing my LBS.

jrenaut
05-03-2012, 05:39 PM
Twice in the past two days the chain has slipped from the middle ring in front to the smallest one - a couple of up and down shifts has gotten it back where it belongs. Other than that, no symptoms.

ronwalf
05-03-2012, 06:37 PM
You can measure the chain yourself with a measuring tape:
http://sheldonbrown.com/chains.html#wear
Scroll down to the section on "Measuring Chain Wear".

Mark Blacknell
05-03-2012, 07:43 PM
Worn chains and cassettes are normally replaced together (a new chain on a worn cassette will get stretched out very quickly). A year replacement interval isn't unreasonable. But that depends on a lot of factors. You asking for crisp and immediate shifting? You'll want to replace it more frequently than not. Not a fan of keeping your drivetrain clean? Yeah, that's another drivetrain killer.

Crankset and bottom bracket? I'm a little more skeptical about that. With respect to the bottom bracket, unless you submerged it or got a crap one, I'd expect it to last a good bit longer than a year. But I know some people who have a talent for one/both of those.

Crankset? Hrm. Maybe, if you've ridden your bike through wet sand on a regular basis, and really ground down the chainring, would I expect a replacement. But the whole crankset? Again - hrm. (Then again, I don't have a lot of experience with stuff below the Shimano 105/SRAM Force lines).

~

In any event, sounds like a good candidate for a Bike Haus or VeloCity night, if you're interested in sorting this out yourself.

brendan
05-03-2012, 08:10 PM
So, I bought my bike the end of May 2011. I started off putting maybe 30 miles a week on it, and worked up to 50-75 miles a week. I do almost all of my riding in the city, and ride in all but the worst weather.

Today I brought my bike in to my LBS for warranty adjustments, and they said I need to replace the chain, cassette, crankset, and bottom bracket. I know I don't clean my chain and gears much, but does this seem excessive? Aside from cleaning, which I know I have to do better, are there other things to do to get a bit more life out of the drivetrain?

Chain & cassette - probably. Its possibly your chain has worn to significantly beyond the "replace at this wear level" level, which helps to grind down the cassette.

What crankset do you have? It's unusual to have to replace that entirely but you may have also worn your most heavily used chainring(s) significantly and one or two rings might need replacement. Perhaps that what they mean by crankset?

Is the bottom bracket creaking and/or loose? Is it loose due to misadjustment or wear?

Since approximately the same time (spring 2011), I've replaced the Big Dummy's chain twice, cassette twice, outer chain rings approximately twice and outboard/external bottom bracket components twice. The "crankset" itself aside from the chain rings (a mr. whirly) remains in good, if scuffed, condition. Granted, I think there has been > 8500 miles on the bike since then.

Had I been more on top of replacing the chain as it wears, it's possible I may not have had to replace the cassette and/or chain rings as often. The last chain was around 3x to 4x the stretch length where they recommend you replace the chain, and the immense slack allowed the derailleur pulley to lay way up against the chainstay. Needless to say, shifting and power-transfer was horrid before replacements. And rather embarrassing for me, really.

Brendan

jrenaut
05-03-2012, 08:20 PM
Would towing a trailer full of children regularly make a difference? Of my 50 or so miles a week, probably 10-15 are pulling the trailer.

off2ride
05-03-2012, 09:21 PM
Now the facts are coming out. To answer your question, YES. Since you're pulling weight, you're accelerating chain wear plus other components in the drive train. Brake wear is also a factor since it requires more power to stop a vehicle with more weight. Especially descending.


Would towing a trailer full of children regularly make a difference? Of my 50 or so miles a week, probably 10-15 are pulling the trailer.

jrenaut
05-03-2012, 09:45 PM
Luckily the normal trip home with both kids in back is almost all uphill. I hardly touch the brakes (so I wear out the expensive parts and not the cheap brake pads).

DaveK
05-04-2012, 09:30 AM
To echo what others have said, it makes sense that after a year of hard use you'd need a new cassette, chain, and chainrings (NOT crankset - short of a nuclear explosion the cranks will last forever). The bottom bracket should last a lot longer.

jrenaut
05-04-2012, 09:58 AM
Thanks, everyone. I feel like I have a much better sense of what I'm in for now. I'll go back to the bike shop soon and talk about my options.

They did specifically write "crankset" on the list of things to be replaced - does $100 + $20 labor sound about right for replacing a crankset? Not so much asking if I should shop it out as just wanting to verify that they mean replacing the whole crankset.

jabberwocky
05-04-2012, 10:07 AM
The only way I could see needing to replace the entire crankset is if its 1)one of the cheap ones with permanently attached rings, and 2)the rings are worn out.

americancyclo
05-04-2012, 10:37 AM
$100 + $20 labor sound about right for replacing a crankset?
That sounds a little low to me. Online prices for a Shimano 105 crankset run about $150. Any idea what kind of components they are trying to put on your bike?

jrenaut
05-04-2012, 10:43 AM
This is the bike (http://www.giant-bicycles.com/en-us/bikes/model/defy.3/7307/44049/). I assume they would put the same components on as what came with it, but that wasn't specified. The website lists the crankset as FSA Tempo, 30/42/52.

jabberwocky
05-04-2012, 10:48 AM
That crankset has replaceable rings. Maybe the price is for new chainrings? Definitely have them clarify, because I can't imagine the actual crankset needs to be replaced unless its broken.

americancyclo
05-04-2012, 11:05 AM
The FSA Tempo shows up on Google shopper for $40 shipped. Also saw it mentioned that it was a square taper on the FSA site. Maybe your high torque damaged the taper of the crank, and that's why it needs to be replaced?

http://www.fullspeedahead.com/products/43/Tempo

Gotta admit i'm a bit out of my element when we start talking about bottom brackets, I'm mostly familiar with Shimano's Hollowtech cranks, which don't use a cartridge bearing.

ronwalf
05-04-2012, 03:45 PM
Would towing a trailer full of children regularly make a difference?

Follow the torque! The torque you apply to the chain (and thus the teeth on the cassette) is from:

Your pressure on the pedal
Crank length
Size (teeth) of the chain ring


That's it! So other than a tendency towards the smallest chain ring, you're not likely to be putting outrageous pressure on the chain and cassette. You might be shaving a few miles off the rear tire and brakes, though.

off2ride
05-04-2012, 08:21 PM
If all 3 chain rings are available then why not just replace the rings. As long as it's compatible, has the right diameter and teeth count. Replace the crank if the threads for the pedal is severely stripped and/or if the pedal spindle broke off. You might have to pay more labor since the bike tech will be dismantling the rings.

creadinger
05-05-2012, 03:08 PM
This is the bike (http://www.giant-bicycles.com/en-us/bikes/model/defy.3/7307/44049/). I assume they would put the same components on as what came with it, but that wasn't specified. The website lists the crankset as FSA Tempo, 30/42/52.

One thing you could do is, as you replace these parts upgrade with durability in mind? I've been trying to do that with my 'Cross bike, replacing the original parts with more durable touring style stuff. I don't race, so I don't need the expensive super light racing parts. I also really do not want the cheap crap, which will have a short lifespan with all the abuse they take.

I echo what most people have mentioned I think - the chain and cassette probably need to be replaced. The other stuff you'll need more information on I think.

jrenaut
07-16-2012, 07:57 AM
I brought the bike to The Bike House over the weekend, where they used a chain tool to confirm that my chain is in need of replacement. The front chain rings are showing signs of wear, too. So I guess I'm going to get some stuff replaced.

Should I just get the same components I have now? Should I think about upgrading to something tougher if I'm going to continue to beat the crap out of my bike?

I can't go from 3 front chain rings to 2 without changing a bunch of other stuff, too? The only time I ever use the small ring is when I accidentally shift twice, and then I only use it long enough to shift back to the middle ring.